Abstract

We evaluated the effect of contrasting pCO(2) levels: lower (390 mu atm), moderate (700 mu atm) and extreme (1000 mu atm), on the scope for growth of the keystone snail Concholepas concholepas over an exposure period of 6 months. Juvenile snails were collected from rocky intertidal habitats and acclimated for 5 months to those pCO(2) levels. Subsequently, three groups of snails were randomly taken (n = 7 for each treatment) and reared for an additional 1 month for each of the three pCO(2) levels. Physiological traits related with energy gain and energy expenditure were quantified. The scope for growth index decreased significantly with increases in pCO(2), yielding negative values throughout the experimental period for the snails exposed to 1000 mu atm pCO(2), probably due to the extra energy required to maintain their metabolic functions in balance. This suggests that future climate change scenarios with elevated pCO(2) levels could threaten the growth and other basic functions of juvenile snails of this species.